In a number of industries, the manufacturing, packing, and processing of various products requires conveying articles of relatively small size and area, and of thin, flat shape, typically cards of plastic or fibrous material, and other objects having portions of such size and shape, in carefully maintained flat, horizontal position, longitudinally along the bed of a conveyor. The conveying may be for the purpose of movement from one station to another in a manufacturing process, or through a station where a step in the process is being performed. In many cases it is desirable or essential that the articles being conveyed be maintained accurately horizontal and at constant speed of movement, as for example in certain medical and laboratory operations where liquids, powders or tablets are dropped into open pockets in cards which are thereafter to be covered and sealed. In other industries, cards or equivalent media bearing printed circuits, particularly miniaturized ones, require careful handling to avoid scratching or other marring by surface contact with conveyor machine elements.
The present invention aims to provide a conveyor, preferably embodied in a module adapted to be connected endwise to other similar modules, all of which may be individually powered, to constitute an installation of any desired length that will move articles of the kind indicated at constant speed in a carefully maintained flat horizontal position, by rollers making propelling engagement in minimal contact with no more than the side edges of the articles.